Catalyst complexes and polymers therefrom

ABSTRACT

The invention is directed towards a metal complex having the formula LMX 1  X 2 . L is a bidentate nitrogen-containing ligand with more than two nitrogen atoms. M is copper, silver, or gold. X 1  and X 2  are independently selected from the group consisting of halogens, C 1  through C 12  straight chain, branched, or cycloalkyl or aryl, C 1  through C 12  straight chain, branched, or cycloalkoxy, hydride, triflate, trifluoroacetate, trisperfluorotetraphenylborate, and tetrafluoroborate. Such metal complexes have a tetrahedral or pseudo-tetrahedral structure. The invention relates to a catalyst composition of the reaction product of the metal complex and an activating cocatalyst. The invention is also directed towards a method for forming polymers and copolymers using such catalyst compositions, especially copolymers having segments formed from olefinic monomers and monomers having at least one hydrocarbyl polar functional group.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. Ser. No. 08/991,160filed Dec. 16, 1997, now abandoned.

FIELD OF THE INVENTION

The invention is directed towards tetrahedral and pseudo-tetrahedrallate transition metal polymerization catalyst complexes and their use informing homopolymers from olefins or polar monomers and copolymers fromolefins and polar monomers.

BACKGROUND

Polymers and copolymers may be formed from olefinic monomers by usingtransition metal metallocene catalyst technology. This well-knowntechnology uses catalysts containing early transition metal atoms suchas Ti and Zr.

Even though polyolefins formed by such metallocene catalysts possesenhanced properties over polyolefins produced by conventionalZiegler-Natta catalysts, further improvements in properties such aswettability and adhesiveness may be possible. It is believed thatincluding polar monomers in an olefinic polymer or copolymer wouldimprove wettability and adhesiveness in those materials. Unfortunately,polar monomers tend to poison early transition metal catalysts.

Certain late transition metal complexes of palladium and nickelincorporate some polar monomers. However, such catalyst systems arecostly. Also, the polymers so produced are highly branched (85-150branches/1000 carbon atoms) and the functionalities are not in the chainbut at the ends of branches. Consequently, they are limited to polarmonomer contents≦about 15 mol %. Another disadvantage of these systemsis that they incorporate only a limited number of polar monomers (e.g.alkyl acrylates and vinyl ketones). Methyl methacrylate and n-butylvinyl ether are mildly inhibiting or inert.

Consequently, there remains a need for a polymerization catalyst capableof forming olefinic polymers and copolymers and that are effectivepolymerization catalysts in the presence of polar monomers.

SUMMARY OF THE INVENTION

In one embodiment, the invention is a catalyst system comprising:

(a) a catalyst having the formula LM X₁ X₂ wherein X₁ and X₂ areindependently selected from the group consisting of halogens, hydride,triflate, acetate, trifluoroacetate, perfluorotetraphenylborate,tetrafluoroborate, ₁ C through ₁₂ C straight chain or branched alkyl oralkoxy, ₃ C through ₁₂ C cyclo alkyl or cycloalkoxy, and aryl; M isselected from the group consisting of Cu, Ag, and Au; and L is anitrogen-containing bidentate ligand, and

(b) an activating cocatalyst.

A method is provided for polymerizing an olefinic monomer selected fromthe group consisting of (a) acyclic aliphatic olefins, (b) olefinshaving a hydrocarbyl polar functinally and (c) mixtures of (i) at leastone olefin having a hydrocarbyl polar functionality and (ii) at leastone acyclic aliphatic olefin, the method comprising contacting theolefin monomer under polymerization conditions with the catalyst systemof this invention.

In still another embodiment, the invention is a substantially linearcopolymer represented by the formula: ##STR1## where A is a segmentderived from an acyclic aliphatic olefin of 2 to about 20 carbon atoms;

R is H or CH₃ ;

X is --OR¹ or --COOR¹ ;

R¹ is an alkyl group of 1 to 24 carbon atoms; and Y is from about 0.02to about 0.95

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the structure of Cu(MeBBIOMe)Cl₂.

FIG. 2 shows the structure of Cu(tribut BBIM)Br₂.

DETAILED DESCRIPTION OF THE INVENTION

The catalyst of this invention is a complex having the formula LM X₁ X₂,wherein L is a nitrogen-containing bidentate ligand represented by theformula:

    [AZA'] and [AA'],

wherein A and A' are independently selected from the group consisting of##STR2## wherein R1 is independently selected from the group consistingof hydrogen, ₁ C through ₁₂ C straight chain or branched alkyl, ₃ Cthrough ₁₂ C cycloalkyl, aryl, and trifluoroethane;

R2 and R3 are independently selected from the group consisting ofhydrogen, ₁ C through ₁₂ C straight chain or branched alkyl, ₃ C through₁₂ C cycloalkyl, ₁ C through ₁₂ C alkoxy, F, Cl, SO₃, ₁ C through ₁₂ Cperfluoroalkyl, and --N(CH₃)₂ ;

Z is selected from the group consisting of non-substituted ₁ C through₁₂ C straight chain or branched alkyl, ₃ C through ₁₂ C cycloalkylmethoxy; amino; halo; and ₁ C through ₁₂ C haloalkyl substitutedstraight chain or branched alkyl or cycloalkyl of up to 12 carbon atomsor ₁ C-₄₀ C aryl or alkylaryl groups.

X₁ and X₂ are independently selected from the group consisting halogens,hydride, triflate, acetate, trifluoroacetate,perfluorotetraphenylborate, and tetrafluoroborate, ₁ C through ₁₂ Cstraight chain or branched alkyl or alkoxy, ₃ C through ₁₂ C cycloalkylor cycloalkoxy, and aryl;

Accordingly, some of the ligands of the present invention have thestructures: ##STR3##

For compactness, some bonds are shown without termination; these bondsare terminated by methyl groups.

The metal M is selected from Cu, Ag, and Au. Among Cu, Ag, and Au, Cu ispreferred; among X₁ and X₂, halogens are preferred.

Suitable non-halide X₁ and X₂ include triflate, trifluoroacetate,perfluorotetraphenylborate, or tetrafluoroborate.

Among the catalyst complexes of the present invention, those having the1,1'-bis(1-methylbenzimidazol-2-yl)1"-methoxyethane ligand or the3,3'(1-ethylbenzimidazol-2yl)-pentane ligand, or2,2'-bis[2-(1-alkylbenzimidazol-2-yl)]biphenyl, where the alkyl group isfrom ₁ C-₂₀ C, and X₁ ═X₂ =chloride are particularly preferred.

1,1'-bis(1-methylbenzimidazol-2-yl)1"-methoxyethane ligands with copperas the metal and chlorine as X₁ and X₂ have the structure ##STR4##

3,3'-bis(1-ethylbenzimidazol-2-yl) pentane ligands with copper as themetal and chlorine as X₁ and X₂ have the structure ##STR5##2,2'bis[2-(1-alkylbenzimidazol-2-yl)]biphenyl ligands with copper as themetal and chlorine as X₁ and X₂, and ₁ C-₂₀ C as R₁, have the structure##STR6##

Advantageously, the catalysts of the present invention are not poisonedby compounds containing hydrocarbyl polar functionalities when used inthe formation of polymers and copolymers synthesized all or in part fromolefinic monomers. As such, the catalysts of the present invention areuseful in preparing polymers and copolymers formed from olefinicmonomers, such as polyethylene; polymers and copolymers formed frommonomers containing hydrocarbyl polar functionalities such aspoly(methyl methacrylate); and copolymers derived from olefins andmonomers containing hydrocabyl polar functionalities such as poly(ethylene-co-methyl methacrylate).

Acccording to the present invention, a catalyst having the formula L MX₁ X₂, wherein L, M, X₁, and X₂ are as previously defined, is combinedwith an activating cocatalyst. Examples of such cocatalysts includealuminum compounds containing an Al--O bond such as the alkylalumoxanessuch as methylalumoxane ("MAO") and isobutyl modified methylalumoxane;aluminum alkyls; aluminum halides; alkylaluminum halides; Lewis acidsother than any of the foregoing list; and mixtures of the foregoing canalso be used in conjunction with alkylating agents, such as methylmagnesium chloride and methyl lithium. Examples of such Lewis acids arethose compounds corresponding to the formula: R""₃ B, wherein R""independently each occurrence is selected from hydrogen, silyl,hydrocarbyl, halohydrocarbyl, alkoxide, aryloxide, amide or combinationsthereof, said R"" having up to 30 nonhydrogen atoms.

It is to be appreciated by those skilled in the art, that the aboveformula for the preferred Lewis acids represents an empirical formula,and that many Lewis acids exist as dimers or higher oligomers insolution or in the solid state. Other Lewis acids which are useful inthe catalyst compositions of this invention will be apparent to thoseskilled in the art.

Other examples of such cocatalysts include salts of group 13 elementcomplexes. These and other examples of suitable cocatalysts and theiruse in organometallic polymerization are discussed in U.S. Pat. No.5,198,401 and PCT patent documents PCT/US97/10418 and PCT/US96/09764,all incorporated by reference herein.

Preferred activating cocatalysts include trimethylaluminum,triisobutylaluminum, methylalumoxane, ethylalumoxane,chlorodiethyaluminum, dichloroethylaluminum, triethylboron,trimethylboron, triphenylboron and halogenated, especially fluorinated,triphenyl boron compounds.

Most highly preferred activating cocatalysts include triethylaluminum,methylalumoxane, and fluoro-substituted triaryl borons such astris(4-fluorophenyl)boron, tris(2,4-difluorophenylboron),tris(3,5-bis(trifluoromethylphenyl) boron, tris(pentafluorophenyl)boron, pentafluorophenyl-diphenyl boron, and bis(pentafluorophenyl)phenylboron. Such fluoro-substituted triarylboranes may be readilysynthesized according to techniques such as those disclosed in Marks, etal., J. Am. Chem. Soc., 113, 3623-3625 (1991).

The catalyst can be utilized by forming the metal complex LM X₁ X₂ andwhere required combining the activating cocatalyst with the same in adiluent. The preparation may be conducted in the presence of one or moreaddition polymerizable monomers, if desired. Preferably, the catalystsare prepared at a temperature within the range from -100° C. to 300° C.,preferably 0° C. to 250° C., most preferably 0° C. to 100° C. Suitablesolvents include liquid or supercritical gases such as CO₂, straight andbranched-chain hydrocarbons such as isobutane, butane, pentane, hexane,heptane, octane, and mixtures thereof; cyclic and alicyclic hydrocarbonssuch as cyclohexane, cycloheptane, methylcyclohexane,methylcycloheptane, halogenated hydrocarbons such as chlorobenzene, anddichlorobenzene perfluorinated C₄₋₁₀ alkanes and aromatic andalkyl-substituted aromatic compounds such as benzene, toluene andxylene. Suitable solvents also include liquid olefins which may act asmonomers or comonomers including ethylene, propylene, butadiene,cyclopentene, 1-hexene, 3-methyl-1-pentene, 4-methyl-1-pentene,1-octene, 1-decene, and 4-vinycylohexane, (including all isomers aloneor in mixtures). Other solvents include anisole, methylchloride,methylene chloride, 2-pyrrolidone and N-methylpyrrolidone. Preferredsolvents are aliphatic hydrocarbons and aromatic hydrocarbon, such astoluene.

In the practice of this invention, it is believed that the cocatalystinteracts with the catalyst to create a polymerization-active, metalsite in combination with a suitable non-coordinating anion. Such ananion is a poor nucleophile, has a large size (about 4 Angstroms ormore), a negative charge that is delocalized over the framework of theanion, and is not a strong reducing or oxidizing agent [S. H. Strauss,Chem. Rev. 93, 927 (1993)]. When the anion is functioning as a suitablenon-coordinating anion in the catalyst system, the anion does nottransfer an anionic substituent or fragment thereof to any cationicspecies formed as the result of the reaction.

The equivalent ratio of metal complex to activating cocatalyst (whereemployed) is preferably in a range from 1:0.5 to 1:10⁴, more preferablyfrom 1:0.75 to 1:10³. In most polymerization reactions the equivalentratio of catalyst:polymerizable compound employed is from 10⁻¹² : to10⁻¹ :1, more preferably from 10⁻⁹ :1 to 10⁻⁴ :1.

The catalysts of the present invention have a tetrahedral orpseudo-tetrahedral structure. It is believed that this structure ispresent when the catalyst is in the form of an isolated solid compoundand when the catalyst is used in the presence of activating cocatalystsof this invention under homopolymerization or copolymerizationconditions.

Olefinic monomers useful in the forming homo and copolymers with thecatalyst of the invention include, for example, ethylenicallyunsaturated monomers, nonconjugated dienes, and oligomers, and highermolecular weight, vinyl-terminated macromers. Examples include C₂₋₂₀olefins, vinylcyclohexane, tetrafluoroethylene, and mixtures thereofPreferred monomers include the C₂₋₁₀ α-olefins especially ethylene,propylene, isobutylene, 1-butene, 1-hexene, 4-methyl-1-pentene, and1-octene or mixtures of the same.

Monomers having hydrocarbyl polar functionalities useful in forming homoand copolymers with the catalyst of the invention, are vinyl ether andC₁ to C₂₀ alkyl vinyl ethers such as n-butyl vinyl ether, acrylates,such as ₁ C to ₂₄ C, or alkyl acrylates such as t-butyl acrylate, andlauryl acrylate, as well as methacrylates such as methyl methacrylate.

In general, the polymerization may be accomplished at conditions wellknown in the prior art for Ziegler-Natta or Kaminsky-Sinn typepolymerization reactions, that is, temperatures from -100° C. to 250° C.preferably 0° C. to 250° C., and pressures from atmospheric to 30,000psig (100 Mpa). Suitable polymerization conditions include those knownto be useful for metallocene catalyst when activated by aluminum orboron-activated compounds. Suspension, solution, slurry, gas phase orother process condition may be employed if desired. The catalyst may besupported and such supported catalyst may be employed in thepolymerizations of this invention. Preferred supports include alumina,silica, and polymeric supports.

The polymerization typically will be conducted in the presence of asolvent. Suitable solvents include those previously described as usefulin the preparation of the catalyst. Indeed, the polymerization may beconducted in the same solvent used in preparing the catalyst.Optionally, of course, the catalyst may be separately prepared in onesolvent and used in another.

The polymerization will be conducted for a time sufficient to form thepolymer and the polymer is recovered by techniques well known in the artand illustrated in the examples hereinafter.

An important feature of the invention is the formation of substantiallylinear copolymers having the formula ##STR7## where A is a segmentderived from an acyclic aliphatic olefin of 2 to about about 20 carbonatoms; R is H or CH₃ ; x is ⁻ OR¹ or ⁻ COOR¹ ; R¹ is an alkyl group of 1to 24 carbon atoms and y is from about 0.02 to about 0.95 andpreferrably y is from about 0.18 to about 0.85.

These copolymers have polar functional monomer segments, ##STR8## whichare substantially in the chain rather than at ends of branches.

In the case where --A-- is a polymer segment derived from ethylene, thebranch content of which is below about 20 branches/1000 carbon atoms,for example from about 0.5 to less than 20 branches.

The invention is further described in the following non-limitingexamples.

EXAMPLES I. CATALYST PREPARATION Example 1

Preparation of 1,1'-bis(1-hydrobenzimidazol-2-yl)carbinol (HBBIOH)

A mixture of 8.0 g of (66.6 mmol) of hydroxypropanedioic acid and 14.41g (133.3 mmol) of 1,2-phenylenediamine in 90 mL of 4 N hydrochloric acidwas refluxed for 18 h. The reaction mixture was cooled and the pH wasadjusted to about 8 with ammonium hydroxide to give a pale-green solid.The solid was collected by filtration and dried in a vacuum oven to give8.85 g of 1,1'-bis(1-hydrobenzimidazol-2-yl)carbinol. Yield: (50.3%); mp238° C. (subl); ¹ H NMR (500 MHz, d⁶ DMSO) δ 7.50 (m, 4H), 7.15 (m, 4H),4.70 (s, 1H), 2.55 (s, 1H). In these examples, NMR resonances areidentified as "m" for multiplet and "s" for singlet. IR absorbtions aredenoted s for strong, m for medium, and w for weak.

Example 2

Preparation of 1,1'-bis(1-methylbenzimidazol-2-yl)1"-methoxyethane(MeBBIOMe)

A 1.0 g (3.8 mmol) quantity of HBBIOH was suspended in 50 ml of dry THF.Under Ar, sodium hydride (80% disperssion in mineral oil, 0.68 g, 22.8mmol) was added to the suspension and was stirred for 0.5 h. A 2.16 g(15.2 mmol) quantity of iodomethane was added dropwise and allowed tostir for 18 h. The reaction mixture was quenched with saturated aqueoussodium sulfate solution. THF was removed by rotory-evaporation. The oilwas washed with water and seperated with methylene chloride followed bychromatography. The 1,1'-bis(1-methylbenzimidazol-2-yl)1"-methoxyethanewas recrystallized from a mixture of 2-propanol and cyclohexane to give0.23 g of solid. Yield 18.9% ; mp 194-195° C.; EI-MS 320; ¹ H NMR(CDCl₃) δ 2.29 (s, 3H), 3.27 (s, 3H), 3.67 (s, 6H), 7.26-7.36 (m, 6H),7.79-7.82 (m, 2H).

Example 3

Preparation of Cu(MeBBIOMe)Cl₂

A solution of ethanol and triethylorthoformate was prepared by refluxing30 ml of 100% ethanol and 4 ml of triethylorthoformate. A 245 mg (1.82mmol) quantity of CuCl₂ (99.999% Aldrich) was dissolved in theethanol/triethylorthoformate solution to form a yellow-green solution.After the addition of 584 mg (1.82 mmol) of solid MeBBIOMe an intenselyyellow colored crystalline precipitate formed. The complex,[1,1'-bis(1-methylbenzimidazol-2-yl)1"-methoxyethane]copper(II)dichloride, Cu(MeBBIOMe)Cl₂, was collected by filtration and dried undervacuum. Measurements revealed a melting point (mp) 262-263° C.(decomposition). Elemental analysis calculations predicted relativeconcentrations of C, 50.19 wt %; H, 4.40 wt %; Cl, 15.61 wt %; and Cu,14.00 Wt %. Laboratory measurements found C, 50.11 wt %; H, 4.48 wt %;Cl, 15.87 wt %; and Cu, 14.1 wt %; The X-ray crystallographic structureis shown in FIG. 1; bond angles are N3-Cu1-Cl2 101.7°, N1-Cu1-Cl1104.6°, Cl2-Cu1-Cl1 105.9°, N3-Cu1-Cl1 126.3°, N1-Cu1-Cl2 129.6°.Accordingly, this compound has a pseudo-tetrahedral structure.

Example 4

Preparation of Cu(tributBBIM)Br₂

A 260 mg (1.16 mmol) quantity of CuBr₂ (99.99% Aldrich) was dissolved in25 mL of ethanol to form an orange-brown solution. After the addition of365 mg (0.88 mmol) of solid 1,1'-bis(1-butylbenzimidazol-2-yl)pentane,(tributBBIM, prepared by the methods of Examples 1 and 2, using malonicacid, 1,2-phenylene diamine and butyl iodide as the alkylating agent, ared-brown solution formed. Then 1 mL of triethylorthoformate was addedto the soultion and filtered. Upon standing the complex,[1,1'-bis(1-butylbenzimidazol-2-yl)pentane]copper(II) dibromide,Cu(tributBBIM)Br₂, formed as long thin red prisms. The crystals werecollected by filtration and air dried, mp 215° C. (decomp.). The X-raycrystallographic structure is shown in FIG. 2; bond angles were measuredto be Br1-Cu1-N11 130.60°, N1-Cu1-Br1 106.4°, N11-Cu1-Br2 99.1°,Br1-Cu1-Br2 100.5°, N1-Cu1-Br2 134.8°. Accordingly, this structure has apseudo-tetrahedral structure.

Example 5

Preparation of [3,3'bis(1-ethylbenzimidazol-2-yl)pentane]copper(II)Dichloride, Cu(tetEtBBIM)Cl₂ and Ditrifluoromethylsulfonate,Cu(tetEtBBIM)(trif)₂

3,3'bis(1-Ethylbenzimidazol-2-yl) pentane copper (II) dichloride,Cu(tetEtBBIM)Cl₂ was prepared by the Examples 1-3, using malonic acidand 1,2 phenylene diamine and ethyl iodide as the alkylating agent. Asuspension of 65 mg of [3,3'(1-ethylbenzimidazol-2-yl)pentane]copper(II)dichloride, Cu(tetEtBBIM)Cl₂, was prepared in a solution consisting of35 ml of methylene chloride and 0.5 ml of triethylorthoformate. To thestirred suspension 67.5 mg of silver trifluoromethylsulfonate, Ag(trif),was added. After stirring about 15 minutes the solution was filtered.After slow evaporation, the filtrate afforded bright blue prisms ofCu(tetEtBBIM)(trif)₂ which were collected by filtration. X-raycrystallographic data revealed a =9.8303 Å, b=10.3048 Å, c=16.1909 Å,α=80.3697°, β=72.7137°, γ=71.4988°, Volume=1480.29 Å³.

Example 6

Preparation of 2,2'bis[2-(1-ethylbenzimidazol-2-yl]biphenyl]copper(II),Cu(diEtBBIL)Cl₂

A solution of ethanol and triethylorthoformate was prepared by combining35 mL of 100% ethanol and 4 mL of triethylorthoformate. A 500 mg (2.93mmol) quantity of CuCl₂ --2H₂ O (Aldrich) was dissolved to form a greensolution. After the addition of 500 mg (1.13 mmol) of solid diEtBBIL,±2,2'-bis[2-(1-ethylbenzimidazol-2-yl)]biphenyl, prepared by the methodof Example 1 and 2, using 2,2'-diphenic acid, 1,2-phenylenediamine, andethyl iodide as alkylating agent, the mixture was refluxed for 5minutes. Upon cooling an orange-brown microcystalline solid wasobtained. The solid was collected by filtration, washed withtriethylorthoformate and pentane, then air dried to give 585 mg oforange-brown solid; mp 206-207° C. (decomp). The orange-brown solid wasrecrystallized from hot nitromethane to give the yellow crystallinecomplex, ±2,2'-[2-(1-ethylbenzimidazol-2-yl)]biphenylcopper(II)dichloride, Cu(diEtBBIL)Cl₂, which was collected by filtration and driedunder vacuum; mp 275° C. (soften) 285° C. (decomp.); Anal. Calcd. Cu,11.01 Found Cu, 11.01; IR(KBr pellet, cm⁻¹)3439 br, 3069 w, 2962 w, 1668s 2947 sh, 2926s, 2852 m, 1465 s, 1418 s, 776 sh, 761 sh, 746 s. X-raycrystallographic data: N1-Cu1-N3 111°; P2(1)2(1), Z=4, a=15.980 Å,c=20.538 Å, α=90°, γ=90°, Volume=5387.36 Å³ ; solution EPR(toluene/nitromethane) A₁₁ =15 Gauss.

Example 7

Preparation of[±2,2'-bis[2-(1-octylbenzimidazol-2-yl)]biphenyl]copper(II) Dichloride,Cu(diOctBBIL)Cl₂

A 200 mg quantity of CuCl₂.2H₂ O (Aldrich) was dissolved in 15 ml ofethanol to give a green solution. Then 100 mg of diOctBBIL, prepared bythe method of Example 1 and 2, using 2,2'-diphenic acid, 1,2phenylenediamine and 1-iodooctane as the alkylating agent, was added asan oil, followed by the addition of 1 ml of triethylorthoformate. Themixture was heated to reflux for 10 min., then allowed to cool. Uponstanding the solution afforded bright-yellow thin plates of[±2,2'-bis[2-(1-octylbenzimidazol-2-yl)]biphenyl]copper(II) dichloride.The crystalline solid was collected by filtration and washed withpentane. Yield 110 mg, MP 152-153° C., Elemental Analysis for Cu: calcd8.52; found 8.45; X-ray crystallographic data: space group P-1, Z=2,a=12.152 Å, b=14.099 Å, c=23.253 Å, α=90.18°, β=90.09°, γ=95.29°,Volume=3967.0 Å³.

II. HOMOPOLYMERIZATION AND COPOLYMERIZATION

Reactions were conducted under argon using Schlenk and gloveboxtechniques. All solvents and monomers were purified by standardtechniques, Perrin, D. D., Armarego, W. L. F. Purification of LaboratoryChemicals; Pergamon: New York, 1988. 30% MAO in toluene, available fromAlbemarle, Inc. (Baton Rouge, La.), was used as received. Generalprocedure for polymer workup: First a sufficient amount of methanol isadded in order to quench the polymerization reaction. Then the mixtureis added to 5 to 10 times its volume of methanol containing 10 ppm of2,6 Di-tertbutyl-4-methylphenol, (BHT), in order to precipitate thepolymer. Then 10 ml of 2 N HCl is added to the mixture containing thepolymer and is soaked for a sufficient time to remove the catalyst andcocatalyst from the polymer. The polymer is generally collected byfiltration and dried under vacuum. "RT" means ambient or roomtemperature, i.e. a temperature from about 20° C. to 26° C.

Example 8

Polyethylene

A glass lined Parr reactor was loaded in an Ar glove box with 14.1 mg(0.024 mmol) of Cu (diEtBBIL)Cl₂ followed by 30 mL of toluene to give apale yellow partially dissolved solution. Next 2.0 mL of 30% MAO wasadded to give a nearly colorless solution. The Parr was sealed and takento a hood containing the controller for the Parr and pressurized with270 psig ethylene and polymerized at 80° C. for ˜24 hours. The reactionwas cooled, vented and quenched with MeOH. The product was collected byfiltration, washed with MeOH and dried at 70° C. for 2 hours.Yield=16.15 g of white polymer. Turnover Number (TON), moles substrateconverted/moles catalyst=24,000. ¹³ C NMR (TCE, Cr(AcAc)₃) δ 29.5(s,--CH₂ --). There were no detectable resonances for branching elsewherein the spectrum, using the method of Randall, J. Macromol. Sci., Rev.Macromol. Chem. Phys. C29 (292) 1989. (Branch content <0.5 branches/1000carbon atoms.) The ¹ H NMR (TCE) δ 1.3 (s, --CH₂ --) δ 0.95(m, CH₃ endgroups)(δ 4.95-5.10(m, olefin end groups). The ratio of CH₃ to olefinend groups was>3:1. Polymer M.sub.η =4,900, Mw=13,900, by GPC (in TCB);Tm=139.1° C., ΔH=209.8 J/g.

Example 9

Polyethylene Polymerization, Hexane Slurry Conditions

Polymerization was run using a hexane slurry prepared by suspending 3.72mg (0.0082 mmol) of Cu(MeBBIOMe)Cl₂ in hexane followed by activationwith 2.5 mL of 10% MAO (0.004 mol). The reactor was pressurized with 125psig of ethylene and heated to 60° C. for 0.5 h to yield 2.4 g of solidpolyethylene (TON=10,900). Polyethylene Mn=150700, MWD=2.33 by GPC (inTCE, polyethylene standard). Polymer T_(m) =140° C.

Example 10

Polyethylene Polymerization, Moderate Pressure Conditions

A high-pressure HASTELLOY™ reactor was loaded in an Ar glovebox with aslurry prepared by suspending 35 mg (0.077 mmol) of Cu(MeBBIOMe)Cl₂ in4.0 mL of toluene followed by activation with 1.0 ml of 30% MAO (0.005mol). The reactor was pressurized with 5.6 g (0.20 mol) of ethylene andheated to 80.5° C., resulting in a pressure of 5170 psig. The pressuredropped to 4390 psig over a 2.75 h period indicating an uptake ofethylene. The polymerization mixture was cooled and quenched withmethanol to give 1.1 g of solid polyethylene. (20% yield based onethylene) Polyethylene Mn=145,400, MWD=2.55, Tm=139° C., ΔH_(f) =122J/g.

Example 11

Polymerization of Ethylene

The polymerization was run using a slurry prepared by suspending 12.8 mg(0.022 mmol) of Cu(diEtBBIL)Cl₂ in 30 mL of toluene and 10 mL of1,2-dichlorobenzene followed by activation with 2.5 ml of 30% MAO togive a yellow suspension. The Parr reactor was pressurized with 500 psigof ethylene and heated to 80° C. and maintained at 80° C. for 1/2 hduring which the pressure dropped from 730 psi to 580 psig. Thepolymerization mixture was cooled and quenched with methanol to give7.97 g of solid polyethylene upon workup (TON=12,700 moles^(PE) /molescatalyst).

Example 12

Polyethylene Polymerization, Toluene Slurry

The polymerization was run using a toluene slurry prepared by suspending20.8 mg (0.029 mmol) of[3,3'(1-ethylbenzimidazol-2-yl)pentane]copper(II)ditrifluoromethyl-sulfonate, Cu(tetEtBBIM(trif)₂ in 30 mL of toluenefollowed by activation with 2.0 mL of 30% MAO (0.01 mol) to give ayellow suspension. The PARR™ reactor was pressurized with 300 psig ofethylene and heated to 90° C. and further pressurized to 750 psig andmaintained at 90° C. for 20 h during which the pressure dropped to 740psi. The polymerization mixture was cooled and quenched with methanol togive 210 mg of solid polyethylene upon workup. Polyethylene Tm=137° C.

Example 13

Copolymerization of Ethylene and 1-hexene

A high-pressure HASTELLOY™ reactor was loaded in an Ar glovebox with aslurry prepared by suspending 30.1 mg (0.066 mmol) of Cu(MeBBIOMe)Cl₂ in2.0 mL of toluene followed by activation with 1.0 mL of 30% MAO (0.005mol). This was followed by the addition of 0.67 g of 1-hexene. Thereactor was pressurized with 4.1 g of ethylene (0.146 mol) and heated to80° C. resulting in a pressure of 850 psig. The pressure dropped to 690psig over a 1.5 h period and the polymerization mixture was cooled andquenched with methanol to give 1.6 g of solid copolymer. (33.5% yieldbased on charge of monomers) Copolymer Mn=133,500, MWD=2.51, Tm=107,123° C.

Example 14

Poly(t-butyl Acrylate)

A 20.1 mg (0.044 mmol) quantity of Cu(MeBBIOMe)Cl₂ was added to a 100 mLround-bottomed flask in an Ar glovebox. A 10 mL quantity of toluene wasadded to the flask, followed by 0.11 g of 30 wt. % MAO (0.57 mmol)resulting in an yellow slurry. 7.45 g of t-butyl acrylate (freshlydistilled from CaCl₂ and stabilized with 300 ppm of phenathiazine) wasadded to the slurry. The flask was covered with aluminum foil and themixture was allowed to stir at room temperature for 18 hours in thedark. At the end of this time period, the reaction was quenched with 5mL of methanol and then the polymer was precipitated out in 150 mL ofacidic methanol (10%). The polymer was isolated by filtration and driedunder vacuum at 40° C. for a day. Yield: 57%. M_(n) =470,000; M_(w)=851,000; MWD=1.8. ¹³ C NMR (ppm, CDCl₃): 28.2 (s, --CH₂--CH(COOC(CH₃)₃)--), 34.3-37.6 (m, --CH₂ --CH(COOC(CH₃)₃)--), 42-43.5(m, --CH₂ --CH(COOC(CH₃)₃)--), 80.5 (m, --CH₂ --CH(COOC(CH₃)₃)--),173.2-174.1 (m, --CH₂ --CH(COOC(CH₃)₃)--), 38% rr, 46% mr, 16% mm (byintegration of methine peak).

Example 15

Poly(methyl Methacrylate)

19.6 mg of Cu(MeBBIOMe)Cl₂ was added to 5 mL of toluene in a 100 mLround-bottomed flask in an Ar glovebox. To another 5 mL quantity oftoluene, 4.41 g of methyl methacrylate (stabilized with 400 ppm ofphenathiazine) was added, followed by 0.15 g of 30 wt. % MAO (0.78mmol). This pale yellow solution was added to the flask, which wassealed and covered with aluminum foil. The reaction mixture was stirredat room temperature for 16 hours in the dark. At the end of this timeperiod, the green-yellow reaction mixture was quenched with methanol andthen the polymer was precipitated out in 150 mL of acidic methanol(10%). The polymer was isolated by filtration and dried under vacuum at50° C. for a day. Yield: 51%. M_(n) =140,000; M_(w) =635,000; MWD=4.6. ¹H NMR (ppm, CDCl₃): 0.86, 1.02, and 1.21 (s, --CH₂ --C(CH₃)(COOCH₃)--),1.5-2.2 (broad m) and 1.91 (s, --CH₂ --C(CH₃)(COOCH₃)--), 3.63 (s, --CH₂--C(CH₃)(COOCH₃)--), 76% rr, 18% mr, 6% mm (by integration of methylpeaks at 0.8 (rr), 1.0 (mr), 1.2 (mm) ppm).

Example 16

Poly n-butyl Vinyl Ether

In an Ar glovebox a yellow suspension was prepared by adding 1.0 ml of30% MAO to 25 ml of toluene containing 10.2 mg (0.022 mmol) ofCu(MeBBIOMe)Cl₂. Then 5.0 mL n-butyl vinyl ether (44 mmol) was added tothe suspension. The mixture was allowed to stir at RT for 20 h duringwhich time the mixture became a viscous pale red-brown solution. Thepolymerization was quenched with methanol. Upon workup 2.07 g ofamorphous poly n-butyl vinyl ether was obtained Yield: 53%, IR (film,KBr plate, cm⁻¹) 2956 (s), 2930 (s), 2871 (s), 1464 (m), 1457 (m), 1377(m), 1039 (s). ¹ H NMR (CDCl₃) δ 0.95 (t,CH₃), 1.3-1.9(m, CH₂),3.3-4.7(m, CH-o, --O--Ch₂); ratio δ 0.95-1.9/δ 3.3-4.7=3H/9H. ¹³ C NMR(CDCl₃) δ 13.5 (s, CH₃), 19.5(s, CH₂ 0, 31.0(s, CH₂)39.0-41.0(m, CH₂),67.5(m, --OCH), 73.5(m,--OCH₂). GPC: Mn=6300, M₂ =30,000.

Example 17

Ethylene/t-Butyl Acrylate Copolymer

A Parr reactor was loaded with 33.5 mg (0.0679 mmol) of Cu (tetEtBBIM)Cl₂ followed by 35 mL of toluene, then by 2.0 mL of 30% MAO (.01moles) in an argon dry box to give a yellow suspension. The 6.0 mL (5.37g) (54 mmol) of t-butyl acrylate was added to give a yellow-greensuspension. The Parr was sealed and set up in a hood and pressurizedwith 750 psig of ethylene and polymerized at 90° C. for 24 hours. Thereaction mixture was cooled and quenched with MeOH. Subsequently, thecontents of the reactor were added to ca 150 mL of MeOH giving a whiteprecipitate. A 10 mg quantity of BHT and 25 mL of HCl were added, andthe mixture was allowed to soak to dissolve catalyst residues. Thepolymer was extracted from the water phase with CH₂ Cl₂ and Et₂ O Thesolvents were removed by vacuum and the polymer was dried in a vacuumoven at 55° C. to give 2.96 g of pale-green solid. Catalyst turnovers(TON) (moles substrate converted per mole of catalyst) for t-butylacrylate is 307, for ethylene is 151.

¹ H NMR (CDCl₃) δ 0.7-0.85 (m CH₃ end groups), δ 1.1-1.25 (m --CH₂ --),δ 1.4 (s --O--C(CH₃)₃)), δ 6 2.05-2.25 (broad m, ##STR9## The presenceof a multiplet rather than a triplet at 2.05-2.25 ppm, and the lack of aresonance at 1.6 ppm is consistent with in chain ester units rather thanester ended branches, such as --(CH₂)_(n) CH₂ COOC(CH₃)₃. Integration ofthe monomer units indicates a copolymer composition of ca 67% t-butylacrylate units and 33% ethylene units. ¹³ C NMR (δ, CDCl₃), δ 27 ppm (t,CH₃ 's of the t-butyl group), δ 67 (s, ##STR10## of t-butyl group), δ41.5-42.8 (m, --CH₂ --), δ 43.8-44.8 (m, --CH₂ --), δ 46.5 (s, --CH--).Branching analysis of CH₃ (at δ 19.8), Et (at δ 11.6), C₃ -C₆ (at δ14.1) by ¹³ C NMR gave ≦4.4 CH₃ branches/1000 C atoms, 7.7 CH₃ CH₂branches/1000 C atoms, and 5.1 propyl to hexyl branches/1000 carbonatoms. GPC (THF, polystyrene calibration, with DRI and UV detection at215 nm) of a sample purified through a neutral alumina column to removeMAO and unreacted monomer: Mn=26,200, Mw=34,200. The presence of UVactivity across the molecular weight distribution is an indication ofcopolymer formation. DSC (Tg=+4 and no Tm) also confirms copolymerrather than homopolymers.

Comparative Example 1

A copolymer was prepared following the procedure of Examples 134 of PCTWO96/23010. ¹ H NMR (CDCl₃): 2.2(t, --CH₂ CO₂ C(CH₃)₃, ester endedbranches), 1.6 (m, CH₂ CH₂ CO₂ C(CH₃)₃, ester ended branches), 1.45 (s,--C(CH₃)₃), 0.95-1.45, (m, CH and other CH₂). 0.75-0.95 (m, CH₃, ends ofhydrocarbon branches or ends of chains). This spectrum shows that theesters are primarily located at the ends of hydrocarbon branches;integration gave 6.7 mole % t-butyl acrylate. ¹³ C NMR quantitativeanalysis, branching per 1000 CH₂ : Total methyls (74.8); methyl (27.7),Ethyl (15.3), propyl 1.5), butyl (8.6), ≧amyl and end of chains (30.8),--CO₂ C(CH₃)₃ ester (43.2). Ester branches --CH(CH₂)_(n) CO₂ C(CH₃)₃ asa % of total ester: n≧5 (44.3), n=1, 2, 3, 4 (37.2), n=0 (18.5). GPC(THF, PMMA standard): Mn=6000 Mw=8310 Mw/Mn=1.39.

Example 18

Ethylene/MMA Copolymer

In an Ar glovebox, a Parr reactor was loaded with 26.1 mg (.055 mmol) ororange Cu (BBIK) Cl₂, followed by 30 mL of toluene, and finally with 2.0mL of 30% MAO (0.010 mol). Then 4.0 mL (3.74 g) (0.0374 mmol) of methylmethacrylate, containing 400 ppm of phenathiazine, was added. The Parrreactor was sealed and set up in a hood and pressurized with 750 psig ofethylene and polymerized at 90° C. for 19.5 hours. The reaction wasquenched with MeOH. The polymer was collected by filtration to give 0.68g of white polymer. Turnover Number (TON) (moles substrate converted formole of catalyst) for MMA=109, for ethylene=50. IR (film, cm⁻¹)3441 w,3001 s, 2951 s, 2943 sh, 1736 s (ester ##STR11## 1456 (CH₂), 1246 s(C--O), 1149 s (C--O), 1000 sh, 991 s, 914 w, 844 m, 812 w, 756 m (CH₂).¹ H NMR (CDCl₃) δ 0.61(m, CH₃ end groups) δ, 0.85-1.1 (m, CH₃). δ1.45-2.45 (m, --CH₂ --), δ 3.25-3.35 (s, --OCH₃). Integration of ¹ H NMRindicates a copolymer composition of 71.3% MMA and 28.7% ethylene. GPC(in TCB, polystyrene calibration): Mn=1,150, Mw=35,900; Tg of polymer-61.2° C. (first heat), no Tm; ¹³ C NMR (CDCl₃), δ 18-22 (m, --CH₂ --),δ 31-32, δ 40-41 (m, --CH₂ --), 45.5-46.5 (m, ##STR12## δ 52.5 (s,--OCH₃), δ 55.8 (m, --CH₂ --). No backbone methine carbons were found bya DEPT (Distortionless Enhancement by Polarization Transfer) experiment,indicating no detectable backbone branch sites.

Example 19

Ethylene/n-Butyl Vinyl Ether Copolymer

A Parr reactor was loaded with 33.3 mg (0.0673 mmol) of Cu (tetEtBBIM)Cl₂ and 30 mL of toluene, followed by the addition of 2.0 mL of 30% MAO(0.010 mol) to give a yellow suspension. A 5 mL quantity (44 mmol) ofn-butyl vinyl ether was added with no immediate color change. The Parrreactor was sealed and taken to a hood containing the controllers forthe reactor. The reactor was pressurized with 750 psig of ethylene andthe mixture was reacted at 60° C. for 20 hours. The reaction was cooled,quenched and the product was isolated. The polymer was soaked inMeOH/HCl to remove catalyst residues. The product was washed and driedto yield 0.420 g of viscous oil. TON (n-butyl vinyl ether) =61; TON(ethylene)=11.5. IR (film, KBr plate, cm⁻¹) 2958(s), 2931(s)(CH₂),2872(s), 1465(s), 1458(s), 1377(m), 1093(s), 1039(m), 979(w), 932(w),913(w), 859(w), 802(m) 737(m) CH₂, ¹³ C NMR (CDCl₃ +CrAcAc)₃ δ 13.5 (s,CH₃), 19.5 (s, CH₂) 29.5-30.0 (m, --CH₂ --), 31.0(s, CH₂) 39.0-41.5 (m,CH₂), 68.5(m, --CH--O), 73.5 (m, --OCH₂). The presence of the --CH--Oresonance at 68.5 ppm indicates an in-chain copolymer. Integration ofthe NMR indicates a copolymer composition of 84.3% n-butyl vinyl ether,and 15.8% ethylene. The polymer Tg=-97, -63° C. with no Tm is consistentwith copolymer formation. GPC (polystyrene calibration with DRI and UVdetection at 215 nm), Mn=5390, Mw=23620, Mw/Mn=4.38. The presence of UVactivity across the molecular weight-distribution confirms copolymerformation.

Example 20

Poly(lauryl Acrylate)

In a nitrogen glovebox, a polymerization tube was loaded with 17.9 mg(FW 744.5, 2.4×10⁻⁵ mole) of Cu(diOctBBIL)Cl₂ catalyst, followed by20.25 mL of toluene, and finally with 0.8 mL of 10% MAO (0.00138 mole).Then 3.0 g (FW 240.39, 0.0125 mole) of inhibitor free lauryl acrylatewas added. The mixture was allowed to stir at room temperature for 24hours. The yield was 47%, upon workup. ¹³ C NMR of the product showedcharacteristic polymer ester peak at 174.4 ppm as against to 166.1 peakfor monomer ester. IR (film, cm⁻¹) 1736 (polymer ester carbonyl), 1464,1396, 1377, 1258, 1167 and 721. GPC (solvent: THF, polystyrenecalibration) of the product gave Mn 16100 and Mw 69100.

Example 21

Ethylene/Lauryl Acrylate Copolymer

In a nitrogen glove box, a Parr reactor was loaded with 15.0 mg (FW744.5, 2.01×10⁻⁵ mole) of Cu(diOctBBIL)Cl₂ catalyst, followed by 30 mLof toluene, and finally with 2.4 mL of 10% MAO (0.00414 mole). Then 2.0g (FW 240.39, 0.00832 mole) of inhibitor free lauryl acrylate was added.The Parr reactor was sealed and set up in a hood and pressurized with700 psig of ethylene and polymerized at 80° C. for 48 hours. The polymerwas collected by filtration to give 1.3 g of product. Turnover number(TON) (moles of substrate converted for mole of catalyst) for LA=234,for ethylene=306. The ¹³ C NMR of the product showed peaks due to bothethylene, as well as lauryl acrylate. Integration of the peak indicatesa copolymer composition of 56.7 mole % ethylene, and 43.3 mole % laurylacrylate. GPC (solvent: THF, polystyrene calibration) of the productgave Mw 7700.

What is claimed is:
 1. A catalyst composition comprising the reactionproduct of:(a) a metal complex having the formula LM X₁ X₂ wherein X₁and X₂ are independently selected from the group consisting of halogens,hydride, triflate, acetate, trifluoroacetate,trisperfluorotetraphenylborate, tetrafluoroborate, C₁ through C₁₂ alkyl,C₁ through C₁₂ alkoxy, C₃ through C₁₂ cycloalkyl, C₃ through C₁₂cycloalkoxy, and aryl; M is selected from the group consisting of Cu,Ag, and Au; and L is a nitrogen-containing bidentate ligand with morethan two nitrogen atoms; and (b) an activating cocatalyst.
 2. Thecatalyst composition of claim 1 wherein L has the formula AZA' or AA'wherein A and A' are independently selected from the group consisting of##STR13## wherein R1 is independently selected from the group consistingof hydrogen, C₁ through C₁₂ alkyl, C₃ through C₁₂ cycloalkyl, aryl, andtrifluoroethyl;R2 and R3 are independently selected from the groupconsisting of hydrogen, C₁ through C₁₂ alkyl, C₃ through C₁₂ cycloalkyl,C₁ through C₁₂ alkoxy, F, Cl, SO₃, C₁ through C₁₂ perfluoroalkyl, and--N(CH₃)₂ ; Z is a divalent hydrocarbyl group wherein the hydrocarbylgroup is selected from the group consisting of C₁ through C₁₂ alkylenesand halogen-substituted alkylenes; C₃ through C₁₂ cycloalkylenes andmethyl-substituted cycloalkylenes; and aromatics and alkylaromatics ofup to 40 carbon atoms.
 3. The catalyst composition according to claim 2wherein L is selected from the group consisting of1,1'-bis(1-methylbenzimidazol-2-yl)-1"-methoxyethane,3,3'-(1-ethylbenzimidazol-2-yl)-pentane, and2,2'-bis{2-(1-alkylbenzimidazol-2-yl)}biphenyl, where the alkyl group isfrom C₁ -C₂₀ atoms.
 4. The catalyst composition of claim 3 wherein theactivating cocatalyst is selected from the group consisting ofalkylalumoxanes, aluminum alkyls, aluminum halides, alkyl aluminumhalides, Lewis acids and alkylating agents, and mixtures thereof.
 5. Thecatalyst composition of claim 4 wherein the ratio of metal complex toactivating cocatalyst is from 1:10⁻² to 1:10⁶.
 6. The catalystcomposition of claim 5 wherein X₁ ═X₂ and are selected from the groupconsisting of chloride, bromide, and trifluoromethylsulfonate.
 7. Thecatalyst composition of claim 2 wherein Z is a divalentmethoxy-substituted hydrocarbyl group.
 8. A method for polymerizingolefinic monomers selected from the group consisting of:(a) acyclicaliphatic olefins, (b) olefins having a hydrocarbyl polar functionalityand (c) mixtures of (i) at least one olefin having a hydrocarbyl polarfunctional group and (ii) at least one acyclic aliphatic olefin, themethod comprising contacting the olefinic monomer or monomers underpolymerization conditions with a catalyst composition comprising (a) acatalyst having the formula LM X₁ X₂, wherein X₁ and X₂ areindependently selected from the group consisting of halogens, hydride,triflate, acetate, trifluoroacetate, perfluorotetraphenylborate,tetrafluoroborate, C₁ through C₁₂ straight chain or branched alkyl oralkoxy, C₃ through C₁₂ cycloalkyl or cycloalkoxy, and aryl; M isselected from the group consisting of Cu, Ag, and Au; and L is anitrogen-containing bidentate ligand with more than two nitrogen atoms,(b) an activating cocatalyst.
 9. The method of claim 8, wherein L hasthe formula [AZA'] or [AA'] wherein A and A' are independently selectedfrom the group consisting of ##STR14## wherein R1 is independentlyselected from the group consisting of hydrogen, C₁ through C₁₂ straightchain or branched alkyl, C₃ through C₁₂ cycloalkyl, aryl, andtrifluoroethyl;R2 and R3 are independently selected from the groupconsisting of hydrogen, C₁ through C₁₂ straight chain or branched alkyl,C₃ through C₁₂ cycloalkyl, C₁ through C₁₂ alkoxy, F, Cl, SO₃, C₁ throughC₁₂ perfluoroalkyl, and N(CH₃)₂ ; Z is selected from the groupconsisting of non-substituted C₁ through C₁₂ straight chain or branchedalkylene, C₃ through C₁₂ cycloalkylene; methoxy-substituted alkylene andC₁ through C₁₂ haloalkyl substituted straight chain or branched alkyleneor cyclo alkylene of up to 12 carbon atoms or a divalent arylene oralkylarylene group of up to 40 carbon atoms.
 10. The method of claim 9wherein the cocatalyst is selected from the group consisting ofalkylalumoxanes, aluminum alkyls, aluminum halides, alkyl aluminumhalides, Lewis acids other than any of the foregoing, alkylating agentsand mixtures thereof.
 11. The method of claim 10 wherein the contactingis at a temperature in the range of from about -100° C. to about 250° C.and at pressures of from about 15 psig to about 30,000 psig.
 12. Themethod of claim 11 wherein the contacting is conducted in a solvent. 13.The method of claim 12 wherein the olefinic monomer is selected frommixtures of (i) at least one olefin having a hydrocarbyl polarfunctional group and (ii) at least one acyclic aliphatic olefin, wherebya copolymer is formed.
 14. The method of claim 12 wherein the solvent isan aliphatic or aromatic hydrocarbon solvent or a halogenated aromaticsolvent, or mixture of thereof.
 15. The method of claim 12 wherein theolefinic monomer is selected from the group consisting of (a) acyclicaliphatic olefins, (b) olefins having a hydrocarbyl polar functionalgroup wherein a homopolymer is formed.